1. Field of the Invention
The present invention relates to a map display apparatus using a direction/distance mark, which easily displays a desired map using the mark indicating a direction from a reference point and a distance from the reference point which is displayed on a screen when various kinds of maps are displayed.
2. Description of Related Art
A map has been widely used and displayed not only by a vehicle navigation apparatus but also by a cellular phone, a portable information terminal, a personal computer, and the like. When such maps are used, a person may want to cause, for example, a navigation apparatus to display another desired map from a currently displayed map, in order to, e.g., confirm a destination to which the person is going to visit.
In such a case, for example, when an address of a location to be displayed is known, a map around the address can be immediately displayed by directly inputting that address. However, when the address is not known, or the address is unclear, a desired map cannot be displayed. In addition, it is troublesome to input the address, and in particular, when the map is displayed with the vehicle navigation apparatus, a person who uses the map is mainly a driver, and therefore, it is dangerous for the driver to do many troublesome steps to display the map, which is not preferable.
When a person wants to display another map from a currently displayed map, a desired map may also be displayed by scrolling the map. This method is less troublesome than inputting the address as described above, and another map can be displayed easily. Not only the navigation apparatus as described above but also other apparatuses widely use this method to display maps.
In order to scroll a map, for example, a direction in which a map is moved may be instructed with a joy stick, and a moving speed may be adjusted according to the amount of inclination of the joy stick. But this method requires an operation device, i.e., the joy stick, and when the vehicle navigation apparatus has the joy stick provided on a remote controller thereof, it is dangerous for the driver to manipulate the remote controller during driving. On the other hand, attaching the joy stick to the vehicle or the navigation apparatus itself means that a projecting object exists at the front of the vehicle, which is not preferable.
Therefore, in recent years, a touch panel is pasted to the vehicle navigation apparatus or the screen of various kinds of portable devices, and the user can perform a predetermined function by touching various kinds of operation portions displayed on the screen with a finger and the like. By using this function, a direction is detected in which the finger and the like touch and trace the screen while a map is displayed, the displayed map is scrolled and displayed as if the displayed map is moved.
Japanese Patent Application Laid-Open (JP-A) No. H9-81032 discloses a technique for displaying a scroll menu having marks with 45 degrees intervals, instructing one of them with a mouse cursor, and having a scroll speed according to a distance between an instructed point and a mark start point. Japanese Patent Application Laid-Open (JP-A) No. 2006-90962 discloses a technique for detecting a length for which a finger comes into contact with and moves on a touch panel display and scrolling a map by detecting a moving direction.
Further, Japanese Patent Application Laid-Open (JP-A) No. 2002-116004 discloses a technique for, in each direction at the top, bottom, right, and left of the screen with respect to a display point displayed on a current screen, searching any number of points such as adjacent cities, towns, villages, regions, and adjacent prefectures, displaying them in portions located in the respective directions of the screen in order, wherein a user performs scroll operation for the amount of operation defined in advance in accordance with the degree of distance from the current point in a direction in which the user, who sees this, considers a desired point exists, and the map is jumped to that region by detecting this, and this is displayed with a predetermined scale.
As described above, for map-displaying process of the vehicle navigation apparatus and various kinds of portable devices, it is effective to paste the touch panel to the surface of the screen displaying the map and scroll the map when the user traces the surface of the screen. When the screen is moved by simply detecting the direction in which the screen is traced, it takes much time to display a distant map. In particular, as illustrated in FIG. 10A, for example, when it is desired to display a distant map by performing scroll operation while a detailed map with a small scale is currently displayed, an extremely large amount of operation and much time are required if the screen is scrolled by simply tracing the screen with the finger and the like as it is.
For this reason, in such a case, the scale of the map is temporarily enlarged as illustrated in FIG. 10B, and the screen is traced while a large region map is displayed, so that the distant map can be displayed in a relatively short time from the detailed map display-state of FIG. 10A. In this method, however, how much degree the scale of the map is changed relies on user's intuition.
In addition, in many cases, the following complicated operation has to be performed: after the map is roughly scrolled to an approximate region, the scale is changed to the detailed map side, and when the desired point is out of the display range in that case, scroll operation is performed on the screen, whereby a desired, detailed map is gradually displayed with the desired point being substantially located in the center of the screen.
Further, a method for displaying a distant map at a relatively high speed without changing the scale to the wide region side as described above even when a detailed map is displayed includes a method in which the direction of scrolling is the direction of tracing with the finger, and the scroll speed is gradually increased as the screen is touched with the finger for a longer period of time in that state.
In this method, however, the distant map is displayed at a high speed while the detailed map is still used, and accordingly, the farther the map is, the more difficult it is to understand how much distance the map is scrolled at the present moment and what kind of region is scrolled and displayed at the present moment. When the screen is scrolled by tracing the screen with the finger and the like as described above, it is necessary to keep on touching the screen until a desired map is displayed, and in particular, it is dangerous for a driver to continue this kind of operation for a long period of time with the vehicle navigation apparatus.